Question: How many ordered pairs can be formed from set A without allowing the first number to be the same as the second number? (set A is: {2,3,4,5,7}) Texts answer:
P (5,2) = 20
I do not understand how they get this answer.

Thank you for the reply! However, I must not have been very clear in my original post. I was meaning, given the question, how do you get the answer of P (5,2). I understand how permutations work, I just do not understand how to answer this specific question.

Like, they have ordered pairs, I am looking for an explanation of why they used permutations and HOW.

Thank you for the reply! However, I must not have been very clear in my original post. I was meaning, given the question, how do you get the answer of P (5,2). I understand how permutations work, I just do not understand how to answer this specific question.

Like, they have ordered pairs, I am looking for an explanation of why they used permutations and HOW.

Well I am equally puzzled by you confusion!
There are five ways to choose the first term of the ordered pair and four ways to choose the second term.
Now by anyone’s understanding that is a permutation of five taken two at a time.

Well I am equally puzzled by you confusion!
There are five ways to choose the first term of the ordered pair and four ways to choose the second term.
Now by anyone’s understanding that is a permutation of five taken two at a time.

What about that do you not understand?

Oh!!! That clears it up. I was not thinking in terms of the number of ways to choose the first and second term. Thank you! It makes sense now.